The determination of near precise location of an object, feature or event is obligatory in various applications, including for radar, sonar, wireless technologies, damage detection, structural health monitoring, positioning or mapping systems, and the like, to perform their function. A common location sensing scheme known as triangulation involves the measurement of distance to an event from a reference point. For triangulation, sensors are placed in at least three separate locales to determine the location of an object situated at a point between the sensors.
Location sensing is particularly useful for damage detection and structural health monitoring (SHM) methods. SHM involves the incorporation of non-destructive test methods into a structure to provide continuous remote monitoring for damage. SHM systems are systems with the ability to detect and interpret adverse changes in a structure, such as an airplane or other aircraft, automobiles, and naval applications, for example. Simple SHM systems that have been implemented in diverse industries generally include the adhesion of strain gauges or thermocouples to monitor changes in strain, frequency and temperature. A common form of SHM that provides minimal data is a “black-box” on aircraft that collect critical flight data.